The two “Rogues” in JJ & The Rogues have, um, gone rogue. Just in the past few weeks, the Fort Worth pop-rock quartet lost a bassist and then, completely out of the blue, a drummer, leaving the group’s main duo in the lurch, which might not be such an insurmountable problem except for the fact that the band’s in the middle of recording an album.

Still, the two “Js,”guitarist/vocalist Jameson Cockerell, 26, and guitarist/keyboardist Josh Townley, 28, are forging ahead. They’ve set their sights on a pair of musical up-and-comers to fill the vacancies. Nolan Robertson, frontman and mastermind of Arlington’s digitized but old-school space-rock outfit The Hendersons (now on hiatus), will replace bassist Chris Carfa, whose departure to go teach English in Thailand was expected. In fact, Robertson has been sitting in on JJ & The Rogues’ studio sessions for months to prepare. Robertson, Townley said, is “a terrifically talented guy. We’ve watched his band and played with them a lot. We noticed how similar our tastes are.”

The JJs and Robertsonare eagerly courting Hendersons drummer Zack Mayo, a longtime friend of Robertson, to take over for Eric Navratil, who quit the band so unexpectedly a couple weeks ago that his former bandmatesand the group’s manager, Liam Harvey, are still trying to come to grips with the news. Navratil is moving to Wyoming. “The shocking thing with [Navratil] is we were actually recording a full day — and we never get full days of recording in on this new record, Sweet Talker — and he was eating with us, and he said, ‘Well, this is probably the most opportune time as any: I’m moving in two weeks,’ ” Harvey said. “That was pretty much it.”

Sitting across from each other at a local watering hole patio a few days ago, Cockerell and Townley traded glances and insisted the news generated no hard feelings. “We’re almost 30, and we know that lives move on,” Townley said. He pointed to Robertson, seven years his junior, and quipped, “So we’re recruiting younger so we don’t have to worry about it.”

Last May, the band released Stare Down, a four-song EP that garnered the band a 2011 Weekly Music Awards nomination for “Comeback Band of the Year.”

Robertson, though younger, is no stranger to the local music scene. He’s spent much of the past couple of years building a buzz with The Hendersons, an outfit that won the best “Acoustic/Folk/Psyschedelia” nod in the 2011 Fort Worth Weekly Music Awards.

If anything, Cockerell and Townley may have to cede some of their long-held creative monopoly to Robertson, but it’s a prospect they welcome. The JJs agreed that Robertson is another songwriting and arranging force to betaken into account.

JJ & The Rogues date back more than a decade to a group of seven high school students, including Cockerell, Townley, and Navratil, who met while performing at regional University Interscholastic League jazz competitions. The teenagers started gathering regularly for jam sessions and eventually landedgigs at places like The Flying Saucer and 8.0, covering much older rock acts like Chicago.

Then, around 2004, that original group disbanded when Townley moved to Austin to attend the University of Texas. When he transferred to the University of Texas at Arlington the following year, he reached out to Cockerell, then at Texas Christian University.

And so JJ & The Rogues were born. This time, Cockerell and Townley set out to write their own music. Carfa joined a few months later, and, after a couple of years of drummer turnover, Navratil also signed on with his old jam buddies.

That iteration of JJ & The Rogues, Cockerell and Townley said, refined their sound over the years to the point that they had found a deep, instinctive musical groove.

The quartet released its first EP, Indifference, in 2009. Then, last May, the band released Stare Down, a four-song EP that garnered the band a 2011 Weekly Music Awards nomination for “Comeback Band of the Year.”

Just as the guys started making real progress on their first album, recording at home, Carfa announced his departure for Thailand — far enough in advance that the band had to get his parts laid down. Then, in late March, Navratil dropped his bomb, sending the group into a frenzy, trying to get his parts recorded before his departure for Big Sky Country. “I think we did a decent job of capturing what we had with them on the record,” Cockerell said.

But he expects JJ’s sound to change, hopefully for the better, with the addition of Robertson and, if all goes as planned, Mayo (neither of whom have contributed to the album).

The band’s next chapter may not truly begin until September, the deadline for finishing the album, a project in which the group and its manager have invested all of their energy. Work on Sweet Talker is why you haven’t seen much of JJ & The Rogues on local stages lately and why you probably won’t for months to come. When they finally do return to the stage, you may have a hard time recognizing them.